Re: 2.6.24-rc4-git5: Reported regressions from 2.6.23

Ingo Molnar
2007-12-10T23:04:50Z

* Ingo Molnar <mingo@elte.hu> wrote:

> * Andrew Morton <akpm@linux-foundation.org> wrote:
>
> > > what do you think? Right now i've got them queued up for 2.6.25 in
> > > both the scheduler-devel and the x86-devel git trees - but can
> > > submit them for 2.6.24 if it's better if we did them there. I've got
> > > no strong opinion either way.
> >
> > printk_clock() doesn't seem terribly important but what's this stuff
> > about effects on udelay/mdelay? That can be serious if they're
> > getting shortened.
>
> since udelay depends on loops_per_jiffy, which is fixed up
> time_cpufreq_notifier(), i dont see how it could be affected by
> frequency changes. (but that's the theory - practice might be
> different)

Stefano Brivio reported udelay()/mdelay() effects in the b43 driver.
(and it caused driver failures for him.)

Stefano, could you please try to sum up your experiences with that
issue? Is it reproducable, and the 5 patches i did fix it? (if yes,
could you try to re-do the mdelay verifications perhaps, to make sure
it's not some other effect interacting here. In theory sched-clock
scaling has no effect on udelay behavior.)

Ingo